[FFmpeg-cvslog] avcodec/lagarith: Fix runtime error: left shift of negative value -1

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Wed May 10 00:50:05 2017 +0200| [ddb2dd7edbccc5596d8e3c039133be8444cb1d02] | committer: Michael Niedermayer

avcodec/lagarith: Fix runtime error: left shift of negative value -1

Fixes: 1424/clusterfuzz-testcase-minimized-6088327159611392

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=ddb2dd7edbccc5596d8e3c039133be8444cb1d02
---

 libavcodec/lagarith.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/lagarith.c b/libavcodec/lagarith.c
index 469eec4232..044497720f 100644
--- a/libavcodec/lagarith.c
+++ b/libavcodec/lagarith.c
@@ -98,7 +98,7 @@ static uint32_t softfloat_mul(uint32_t x, uint64_t mantissa)
 
 static uint8_t lag_calc_zero_run(int8_t x)
 {
-    return (x << 1) ^ (x >> 7);
+    return (x * 2) ^ (x >> 7);
 }
 
 static int lag_decode_prob(GetBitContext *gb, uint32_t *value)